In order to identify individuals based on his/her face image or read his/her expression, it is important to detect a face direction, in other words, a central location of the face.
A known image processor capable of detecting a face direction from an inputted face picture of an unspecified individual without previously acquiring the face image data of the object has been disclosed in, for example JP2001-291108A. In this known image processor, an average front face picture data is generated based on plural sample front face picture data, and then average face model data is generated by mapping the average front face picture data onto standard face shape model data.
Based on the degree of correlation between the inputted picture and an average face picture data by angles at a time when the average face model data is seen from a predetermined angle, a face direction in the input picture can be detected.
In addition, a known face orientation estimating device disclosed in JP2004-94491A detects an angle of the face in a captured image. Specifically, the face orientation estimating device rotates an assumed 3D face model, which corresponds to a face line and positions of the eyes prepared in advance, in various angles so as to match to an input image and determine an angle of the model at which fie image matches to the face line and the positions of the eyes.
However, according to the image processor disclosed in JP2001-291108A, templates depending on various sizes of face and various face directions need to be prepared and, because the input picture needs to be matching calculated with each of templates, it has imposed an enormous load on the image processor.
On the other hand, the face orientation estimating device disclosed in JP2004-94491A uses a flat template, however, because human faces, especially hair styles significantly differ among individuals, a lines of his/her face and positions of eyes does not agree with the flat template many times.
In this condition, considering such differences, if the individuals are matched with such flat templates, a great number of face models need to be prepared in advance, as a result, the amount of the processes is increased.
A need exist to provide a central location of a face detecting device, method and program by which calculation load is reduced without face model data.